The invention relates to an apparatus for filleting beheaded and gutted fish, comprising a cutting unit for filleting the fish, wherein the cutting unit has at least one pair of circular blades, an endlessly rotating transport conveyor having at least one saddle-shaped supporting body for receiving the fish and conveying them through the cutting unit tail first, wherein each supporting body has a supporting edge for making a form-locking connection with the centre bone of the fish to be processed, and a device for centring the centre bone in relation to the supporting body.
Furthermore the invention relates to a method for filleting beheaded and gutted fish, having the steps of: transporting a fish resting with its centre bone on a supporting edge of a supporting member with the back at the top, tail first through an apparatus for filleting fish, wherein during transport the dorsal bones are cut free by means of a pair of circular blades.
Apparatuses and methods of this kind are used in the fish-processing industry to separate the fillets from the skeleton of the fish. To be more precise, the ventral belly spokes and/or the dorsal back spokes are cut free. To cut the spokes free, it is necessary for the fish, which are usually transported tail first and with the back at the top, to be delivered to the cutting apparatus in centred fashion. For this, the beheaded and gutted fish are mounted on supporting bodies, the so-called transport saddles. So that the fish stay on the transport saddles, the upper side of the transport saddles is provided with a supporting edge. Usually, the transport saddles on their upper side have teeth which catch in the centre bone of the fish and so form a form-locking connection. For some fish species, it is sufficient to provide one row of teeth. In particular salmonid fish species have a centre bone in which, in the region of the belly cavity, the rib appendages extend from the centre bone at a narrow angle over the whole length of the centre bone uniformly, so that the teeth catch centrally under the centre bone. The rib appendages projecting narrowly from the centre bone form, as it were, a guide, so that the centre bone always rests centrally on the supporting edge of the supporting body. In other words, the rib appendages prevent the centre bone from slipping off the supporting body. By means of the centring device, which usually comprises a pair of flaps which can move towards and away from each other in synchronisation, the fish can then be finely centred for the cutting process.
Other fish species, in particular the white fish species, have a centre bone having a shape which varies over the length. To put it another way, in the region of the belly cavity the position of the rib appendages relative to the centre bone varies from the tail end of the belly cavity towards the head end of the belly cavity. While the rib appendages at the tail end of the belly cavity have a similar orientation relative to the centre bone to the salmonid fish species, namely at a narrow angle to the centre bone, this position varies towards the head, such that the rib appendages in the region of the head end of the belly cavity extend from the centre bone at a wide angle, namely almost horizontally. As a result of this shape of the centre bone or, to be more precise, the orientation of the rib appendages, when mounted on the transport saddle the centre bone leans to one of the two sides of the row of teeth, as the supporting or guiding function of the closely adjacent rib appendages is missing. In other words, the centre bone tilts away from the row of teeth in the region of the rib appendages laterally extending from the centre bone, so that fine centring by the centring device is made difficult. The consequence is incorrect cuts to the fillet. For this reason, transport saddles which have a double row of teeth have been used for such fish species.
A transport saddle of this kind is known e.g. from DE 34 03 771 C1. By this means the centre bone can be mounted in such a way that the centre bone lies centrally between the two rows of teeth. However, a transport saddle with two rows of teeth has considerable drawbacks. Due to the required thickness of a transport saddle of this kind transversely to the direction of transport T, such a transport saddle forms an obtrusive contour for various units. A further drawback lies in that the cutting unit or the circular blades cannot cut close enough to the skeleton, so that the uncut regions of the fillet are torn from the skeleton.